Digital target acquisition system

ABSTRACT

A digital target acquisition system for assisting the operators of manually controlled theodolites acquiring fast maneuvering targets. The system compares the pointing angles of a theodolite to acquisition orders transmitted by a remote range-control central and supplies the theodolite operator with visual error indications that will enable him to train his camera on the designated target. The system is capable of simultaneously assisting the operators of up to four theodolites in acquiring four different targets.

[ 51 3,680,093 July 25, 1912 United: States Patent Brown:

Schroader et al.....................244/3 l3 a a. H Nd "on a e Pd m wm i CNM 3005 $666 9999 1111 HWHU l l 1297 7872 @799 456 2223 [54] DIGITAL TARGET ACQUISITION SYSTEM [7211 Inventor: Claude W. Brown, China Lake, Calif.

[73135 Assignee: The

United States of America as [2211..Filed:

21. Appl.No.i

57 ABSTRACT A digital target acquisition system for assisting the operators of manually controlled theodolites acquiring fast maneuvering ....G0ls9/02 targets, The tem com ares the pointing angles of a' [.58] Field gfiyg theodolite to acquisition orders transmitted by a remote .343 ED, 343/5 DP, 34316 R r [51] Int.1Cl...............

L C M U n 5 range-control central and supplies the theodolite operator with visual error indications that will enable him to train his [56] References Cited UNITED STATES PATENTS camera on the designated target. The system is capable of simultaneously assisting the operators of up to four theodolites in acquiring four different targets.

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sum an [IF 20 I flSEC sEc ,aszFI'hsEc'I I TuSEc I I I I 56 I I I I I I I I I I I I I I I I 1 flBSEC 4O 1 40 C ,assc ,asa

I- COMPLETE MESSAGE I520 flSEC FIG. 3.

DEMODULATED WAIT FOR NEXT TAS IMESSAGES SYNCHRONIZAT|QN $0M PULSE M AND DECODING PULSE WIDTH 32 ,ussc

SOM DETECTION Z'ZE'ES FIG. IO.

STORE ADDRESS AND START BIT COUNTER END OF FIRST I I2BIT COUNT MESSAGE ADDRESSED TO one OF THE SITE'S STATIONS CLOSE SHIFT GATES BY RESETTING SOM DETECTOR SHIFT ORDERS INTO STORAGE REGISTER AND KEEP BIT COUNTER ON END OF SECOND END OF THIRD IZ-BIT COUNT I2--BIT COUNT ORDER AND ORDER AND TIMING TIMING r STATION RAIL I L u g I PATENTEII IIL I972 36 m momw m noww ADTII I l I I I I I L ADS "1 I I I I l I J ADTI 7[ I 201 i I 0 2 F u 5 0 I E E H s LEVATION TIMING AZIMUTH AND LE IMO IMC

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POSITION COMPARISON TIMING MESSAGE DECODE SHEET 06 HF 2D T0 ADI A32 [OI-l 7 v movw BLINK CONTR B4KA ADS

PMENIEDJIJLQS I972 m noew u nonm an a2 B4 B4 Pi I N 1 I0 2 (D 2 szos SZOI THROUGH 204 ARE THE STATION-Z OCTAL SWITCHES AND ARE SHOWN SET TO PAIEN TED JUL 2 5 m2 SHEET 19 0F 20 POSITIONING ORDER (PO) 00| 00| OIO 000 ENCODER READING (EN) 000 I00 I01 000 ERRoR (E) 000 100 Im ooo= ZEROING woRo (ZE) 000 m0 me me TRUE ERRoR (TE) 000 m0 010 me PO 000 011 I00 100 20 DEG EN 000 me Im 000 26 i E III IIo III 100 354 zE 000 010 m0 100 13 TE III I00 I01 000 341 POSITIONING p0 oRoER (PO) III 110 III 100 354056 I EN LOS ENCODER READINGlEN) 000 I00 IoI 000 2s ERRoR RE- MAINDER (E) III 010 m0 100 32a ZEROING woRu (2E) 000 m0 010 I00 I3 TRUE ERROR TE III 000 000 000 315 TWO'S cou- \E E. PLEMENT (2) ooI 000 000 000 4a 

1. A target acquisition system for use in a complex including a remote range-control central and a number of controlled acquiring stations comprising; means at the acquiring station for receiving and decoding messages addressed to it; said messages including azimuth and elevation instructions which comprise a positioning order for said acquiring station; position encoders at the acQuiring station which output azimuth and elevation signals corresponding to that station''s relative azimuth and elevation; position comparing means at said acquiring station for comparing the encoder readings with said positioning orders to obtain an error signal representative of azimuth and elevation; said position comparing means including; an encoder register for storing the pointing angle of a controlled station; an accumulator containing a positioning order at the start of each cycle; zeroing means at said acquiring station for compensating for differences between the readings of the position encoders at the acquiring station and the true azimuth and elevation of the acquiring station and outputting a zeroing signal; wherein said zeroing means contains a correction factor representing the difference between said encoder register reading and the true angle of said controlled station; and true error determining means for comparing the error signal and the zeroing signal to obtain a true error signal representative of azimuth and elevation.
 2. A target acquisition system for use in a complex including a remote range-control central and a number of controlled acquiring stations comprising; means at the acquiring station for receiving and decoding messages addressed to it; said messages including azimuth and elevation instructions which comprise a positioning order for said acquiring station; a message address in said message which includes azimuth and elevation instructions; a storage register for storing said message address; shift gates operatively connected between the start-of-message detector and said storage register so that the message address may be shifted into the storage register upon receipt of a start-of-message portion; position encoders at the acquiring station which output azimuth and elevation signals corresponding to that station''s relative azimuth and elevation; position comparing means at said acquiring station for comparing the encoder readings with said positioning orders to obtain an error signal representative of azimuth and elevation; zeroing means at said acquiring station for compensating for differences between the readings of the position encoders at the acquiring station and the true azimuth and elevation of the acquiring station and outputting a zeroing signal; true error determining means for comparing the error signal and the zeroing signal to obtain a true error signal representative of azimuth and elevation; said message also including a start-of-message portion; and wherein the means at the acquiring station for receiving and decoding messages includes a start-of-message detector which is switched on whenever the decoder detects a start-of-message portion.
 3. A target acquisition system as set forth in claim 2 and further including; an address detection circuit operatively connected to said storage register for comparing the address stored in the storage register with a preset address in the address detection circuit.
 4. A target acquisition system as set forth in claim 3 wherein said controlled acquiring station comprises; a theodolite camera with a sighting telescope mounted thereon; and said error determining system further includes an error determination circuit coupled to the true error determining means for converting the error angle into square wave signals.
 5. A target acquisition system as set forth in claim 5 and further including; indicator lamps on the telescope eyepiece which are provided to indicate to an operator the magnitude of error angle.
 6. A target acquisition system as set forth in claim 5 and further including; an error sign control circuit operatively coupled to the error determination circuit for indicating the direction of error angle which includes left, down, right or up lamp indications.
 7. A target acquisition system as set forth in claim 6 wherein; the error determination circuit converts the error angle into square wave signals that are used to drive the lamps of the sighting telescope eyepiece in one of four standard modes; steady on when the error angle is larger than or equal to 45*, blinking at a 5-cps rate when the error angle is smaller than 45* but larger than or equal to 1.4*, blinking at a 2.5 cycle per second rate when the error signal is smaller than 1.4* but larger than zero and off when the angle error is zero.
 8. A target acquisition system as set forth in claim 3 wherein the address detecting circuit comprises; address select switches, the number of sets of which correspond to the number of controlled stations; address coincidence gates corresponding in number to the sets of switches and receiving the outputs therefrom; enabling means; said coincidence gates also receiving an enabling pulse from said enabling means; and address detection flip-flops, the number of which correspond to the number of sets of switches, receiving the output of said coincidence gates for providing an enabling pulse to said comparison means.
 9. A target acquisition system as set forth in claim 8 and further including; address latch circuit means for producing an inhibit output upon receipt of an output from any one of said address detection flip-flops; said inhibit output being coupled to the input of said respective address coincidence gates for inhbiting the output therefrom until the end of a message. 